diff --git a/author- RIYA SINGHAL(1).c b/author- RIYA SINGHAL(1).c
index 0cf263e..5c21802 100644
--- a/author- RIYA SINGHAL(1).c	
+++ b/author- RIYA SINGHAL(1).c	
@@ -2,13 +2,13 @@
 #include <stdio.h>
 int main()
 {
-    int x;
+    int x,i;
     printf("enter the no. to be divided");
-    scanf("%d",x);
-    for(int i=0;i<=5;i+=1)
+    scanf("%d",&x);
+    for(i=0;i<=5;i+=1)
     {
         int y=x/i;
         printf("\n the quotient after dividing the given no. by %d is %d",i,y)
     }
     return 0;
-}
\ No newline at end of file
+}
diff --git a/author- RIYA SINGHAL(3).c b/author- RIYA SINGHAL(3).c
index 0057de6..208da7f 100644
--- a/author- RIYA SINGHAL(3).c	
+++ b/author- RIYA SINGHAL(3).c	
@@ -1,12 +1,11 @@
-
 #include <stdio.h>
 
 int main()
 {
-    int x=10;
-    for(int i=0;i<5;i-=1)
+    int x=10,i;
+    for(i=0;i<5;i+=1)
     {
-        int x=9;
+        x=9;
         printf("the value of x variable is %d",x);
         
     }
diff --git a/author- RIYA SINGHAL(3).exe b/author- RIYA SINGHAL(3).exe
new file mode 100644
index 0000000..984951b
Binary files /dev/null and b/author- RIYA SINGHAL(3).exe differ
diff --git a/author- RIYA SINGHAL(4).c b/author- RIYA SINGHAL(4).c
index 7ae8bb8..0c030eb 100644
--- a/author- RIYA SINGHAL(4).c	
+++ b/author- RIYA SINGHAL(4).c	
@@ -1,18 +1,17 @@
-
 #include <stdio.h>
 
 int main()
 {
-    int x=10;
-    for(int i=0;i<5;i-=1)//INFINITE LOOP
+    int x=10,i;
+    for(i=0;i<5;i+=1)//INFINITE LOOP
     {
-        int x=9;
+        x=9;
         printf("the value of x variable is %d",x);
         
     }
-    char x;//ALREADY DECLARED ABOVE
+    char y;//ALREADY DECLARED ABOVE
     printf("enter any character");
-    scanf("%c",&x);
-    printf("the entered character is %c",x);
+    scanf("%c",&y);
+    printf("the entered character is %c",y);
     return 0;
 }
diff --git a/author- RIYA SINGHAL(4).exe b/author- RIYA SINGHAL(4).exe
new file mode 100644
index 0000000..eb6b591
Binary files /dev/null and b/author- RIYA SINGHAL(4).exe differ
diff --git a/author- RIYA SINGHAL(5).c b/author- RIYA SINGHAL(5).c
index ba959fd..7c7225c 100644
--- a/author- RIYA SINGHAL(5).c	
+++ b/author- RIYA SINGHAL(5).c	
@@ -2,9 +2,11 @@
 
 int main()
 {
-    int x=10;
-    for(int i=0;i<5;i-=1){
-        int x=9;
-    printf(x);}
+    int x=10,i;
+    for(i=0;i<5;i+=1)
+	{
+        x=9;
+        printf("%d",x);
+	}
     return 0;
 }
diff --git a/author- RIYA SINGHAL(5).exe b/author- RIYA SINGHAL(5).exe
new file mode 100644
index 0000000..84812e5
Binary files /dev/null and b/author- RIYA SINGHAL(5).exe differ
diff --git a/author-AKSHITA(2).c b/author-AKSHITA(2).c
index c0984f2..b8a72c7 100644
--- a/author-AKSHITA(2).c
+++ b/author-AKSHITA(2).c
@@ -5,14 +5,15 @@ int main()
    printf("Enter an integer: ");
    scanf("%d", &num);
    temp=num;
-   while(temp!=0)
+   while(num!=0)
    {
-      remainder=temp%10;
+      remainder=num%10;
       reverse_num=reverse_num*10+remainder;
-      temp/=10;
-   if(reverse_num==num) 
-      printf("%d is a palindrome number",num);
+      num/=10;
+  }
+   if(temp==reverse_num) 
+      printf("%d is a palindrome number",temp);
    else
-      print("%d is not a palindrome number",num);
+      printf("%d is not a palindrome number",temp);  
    return 0;
-}
\ No newline at end of file
+}
diff --git a/author-AKSHITA(2).exe b/author-AKSHITA(2).exe
new file mode 100644
index 0000000..4cbae1c
Binary files /dev/null and b/author-AKSHITA(2).exe differ
diff --git a/author-ALI RAZA.c b/author-ALI RAZA.c
index 665a17d..40f880a 100644
--- a/author-ALI RAZA.c	
+++ b/author-ALI RAZA.c	
@@ -1,5 +1,5 @@
 # include <stdio.h>
-void fun(int &x)
+void fun(int *x)
 {
     *x = 30;
 }
@@ -7,8 +7,8 @@ void fun(int &x)
 int main()
 {
   int y = 20;
-  fun(y);
-  printf("%d", *y);
+  fun(&y);
+  printf("%d", y);
   return 0;
 }
 
diff --git a/author-ALI RAZA.exe b/author-ALI RAZA.exe
new file mode 100644
index 0000000..bc46629
Binary files /dev/null and b/author-ALI RAZA.exe differ
diff --git a/author-ALWINDER(1).c b/author-ALWINDER(1).c
index 77b51f5..a27f67b 100644
--- a/author-ALWINDER(1).c
+++ b/author-ALWINDER(1).c
@@ -7,7 +7,7 @@ void fun(int *p)
 int main() 
 { 
   int r = 20; 
-  int *p = &*r; 
+  int *p = &r; 
   fun(p); 
   printf("%d", *&*&*p); 
   return 0; 
diff --git a/author-ALWINDER(1).exe b/author-ALWINDER(1).exe
new file mode 100644
index 0000000..40bdf7f
Binary files /dev/null and b/author-ALWINDER(1).exe differ
diff --git a/author-CHANDAN(1).c b/author-CHANDAN(1).c
index d2f53db..8061f9d 100644
--- a/author-CHANDAN(1).c
+++ b/author-CHANDAN(1).c
@@ -8,7 +8,8 @@ int main()
     scanf("%d",&a);
     printf("\nEnter value of b = ");
     scanf("%d",&b);
-    sum=a+bsub=a-b;
+    sum=a+b;
+	sub=a-b;
     printf("\nSum: %d\nSub: %d",sum,sub);
     return 0;
 }
diff --git a/author-CHANDAN(1).exe b/author-CHANDAN(1).exe
new file mode 100644
index 0000000..bb4edb4
Binary files /dev/null and b/author-CHANDAN(1).exe differ
diff --git a/author-GURSANGAT(1).c b/author-GURSANGAT(1).c
index 1faf009..237bfb1 100644
--- a/author-GURSANGAT(1).c
+++ b/author-GURSANGAT(1).c
@@ -1,22 +1,25 @@
 # include <stdio.h>
 int main()
 {
-   int i = 0;
+   int i;
    for (i=0; i<20; i++)
    {
-     switch(i);
+     switch(i)
      {
        case 0:
          i += 5;
+         break;
        case 1:
          i += 2;
+         break;
        case 5:
          i += 5;
+         break;
        default:
          i += 4;
          break;
      }
-     printf("%c  "; i);
+     printf("%d  ",i);
    }
    return 0;
-}
\ No newline at end of file
+}
diff --git a/author-GURSANGAT(1).exe b/author-GURSANGAT(1).exe
new file mode 100644
index 0000000..34e439d
Binary files /dev/null and b/author-GURSANGAT(1).exe differ
diff --git a/author-GURSANGAT(2).c b/author-GURSANGAT(2).c
index 2695849..464ee1e 100644
--- a/author-GURSANGAT(2).c
+++ b/author-GURSANGAT(2).c
@@ -1,11 +1,11 @@
-#include<stdi0.h>
+#include<stdio.h>
 
 int main()
 {
     char ch;
     int i;
-    scanf("%c", i);
-    scanf("%d", ch);
-    printf("%c %d", &ch, &i);
+    scanf("%c", &ch);
+    scanf("%d", &i);
+    printf("%c %d", ch, i);
     return 0;
 }
diff --git a/author-HIYA MADAN(2).exe b/author-HIYA MADAN(2).exe
new file mode 100644
index 0000000..2a90699
Binary files /dev/null and b/author-HIYA MADAN(2).exe differ
diff --git a/author-JASKIRAT SINGH(1).c b/author-JASKIRAT SINGH(1).c
index 9cd43ba..5e18c47 100644
--- a/author-JASKIRAT SINGH(1).c	
+++ b/author-JASKIRAT SINGH(1).c	
@@ -1,6 +1,5 @@
 #include<stdio.h>
-
-void transpose(int arr[][],int n)
+void transpose(int arr[][10],int n)
 {
 	int tra[n][n],i,j;
 	for(i=0;i<n;i++)
@@ -17,29 +16,30 @@ void transpose(int arr[][],int n)
 			arr[i][j]=tra[i][j];
 		}
 	}
+	for(i=0;i<n;i++)
+	{
+		for(j=0;j<n;j++)
+		{
+			printf("%d\t",arr[i][j]);
+		}
+		printf("\n");
+	}
 	
 }
 int main()
 {
-	int n,i,j;
+	int k,i,j;
 	printf("Enter the order of matrix\n");
-	scanf("%d",&n);
-	int arr[n][n];
+	scanf("%d",&k);
+	int arr[k][k];
 	printf("Enter the elements");
-	for(i=0;i<n;i++)
+	for(i=0;i<k;i++)
 	{
-		for(j=0;j<n;j++)
+		for(j=0;j<k;j++)
 		{
 			scanf("%d",&arr[i][j]);
 		}
 	}
-	transpose(arr,n);
-	for(i=0;i<n;i++)
-	{
-		for(j=0;j<n;j++)
-		{
-			printf("%d\t",arr[i][j]);
-		}
-		printf("\n");
-	}
+	transpose(arr,k);
+	return 0;
 }
diff --git a/author-JASKIRAT SINGH(1).exe b/author-JASKIRAT SINGH(1).exe
new file mode 100644
index 0000000..7201767
Binary files /dev/null and b/author-JASKIRAT SINGH(1).exe differ
diff --git a/author-JASKIRAT SINGH(2).c b/author-JASKIRAT SINGH(2).c
index 29f0bcc..7c9c088 100644
--- a/author-JASKIRAT SINGH(2).c	
+++ b/author-JASKIRAT SINGH(2).c	
@@ -6,6 +6,6 @@ int main()
 	{
 		printf("division");
 	}
-	printf("%d",5/i);
+	printf("%d",i/5);
 	return 0;
 }
diff --git a/author-JASKIRAT SINGH(2).exe b/author-JASKIRAT SINGH(2).exe
new file mode 100644
index 0000000..81e06b4
Binary files /dev/null and b/author-JASKIRAT SINGH(2).exe differ
diff --git a/author-PALAK AGRAWAL(1).c b/author-PALAK AGRAWAL(1).c
index 30746ac..eb5aa90 100644
--- a/author-PALAK AGRAWAL(1).c	
+++ b/author-PALAK AGRAWAL(1).c	
@@ -1,14 +1,14 @@
 #include <stdio.h>
 int main()
 {
-	int arr={23,45,132,90,345,1,45,8};
-	int sum=sum_arr(arr[],8);
+	int arr[]={23,45,132,90,345,1,45,8};
+	int sum=sum_arr(arr,8);
 	printf("Sum=%d",sum);	
 	return 0;
 }
 int sum_arr(int arr[],int n)
 {
-	int sum;
+	int sum=0,i;
 	for(i=0;i<n;i++)
 	{
 		sum=sum+arr[i];
diff --git a/author-PALAK AGRAWAL(1).exe b/author-PALAK AGRAWAL(1).exe
new file mode 100644
index 0000000..aed511c
Binary files /dev/null and b/author-PALAK AGRAWAL(1).exe differ
diff --git a/author-PALAK AGRAWAL(2).c b/author-PALAK AGRAWAL(2).c
index 702f4e1..ea501af 100644
--- a/author-PALAK AGRAWAL(2).c	
+++ b/author-PALAK AGRAWAL(2).c	
@@ -1,10 +1,10 @@
 #include <stdio.h>
 int isprime(int n)
 {
-	int i,f,c;
-	for(i=0;i<n;i++)
+	int i,f,c=1;
+	for(i=2;i<n;i++)
 	{
-		if(n%c==0)
+		if(n%i==0)
 		c++;
 	}
 	if(c==2)
@@ -15,15 +15,17 @@ int isprime(int n)
 	{
 		f=0;
 	}
+	return f;
 }
 int main()
 {
 	int num;
 	printf("Enter a number:");
-	scanf("%d",num);
+	scanf("%d",&num);
 	int r=isprime(num);
-	if(r==1)
+	if(r==0)
 	printf("%d is prime",num);
 	else
 	printf("%d is not prime",num);
+	return 0;
 }
diff --git a/author-PALAK AGRAWAL(2).exe b/author-PALAK AGRAWAL(2).exe
new file mode 100644
index 0000000..f495bef
Binary files /dev/null and b/author-PALAK AGRAWAL(2).exe differ
diff --git a/author-RIYA SINGHAL(2).c b/author-RIYA SINGHAL(2).c
index 6d13249..ca3d308 100644
--- a/author-RIYA SINGHAL(2).c	
+++ b/author-RIYA SINGHAL(2).c	
@@ -1,13 +1,12 @@
-
 #include <stdio.h>
-int Main()
+int main()
 {
-    int x,y;
-    Printf("enter the no. to be divided");
+    int x,y,i;
+    printf("enter the no. to be divided");
     scanf("%d",&x);
-    for(int i=1;i<=5;i+=1);
+    for(i=1;i<=5;i+=1)
     {
-        x+i=y;
+        y=x+i;
         printf("\n the sum of given number with %d is %d",i,y);
     }
     return 0;
diff --git a/author-RIYA SINGHAL(2).exe b/author-RIYA SINGHAL(2).exe
new file mode 100644
index 0000000..8425746
Binary files /dev/null and b/author-RIYA SINGHAL(2).exe differ
diff --git a/author-SANCHAY JOSHI(1).exe b/author-SANCHAY JOSHI(1).exe
new file mode 100644
index 0000000..dba6c89
Binary files /dev/null and b/author-SANCHAY JOSHI(1).exe differ
diff --git a/author-SANCHAY JOSHI(2).c b/author-SANCHAY JOSHI(2).c
index d180938..a3624e7 100644
--- a/author-SANCHAY JOSHI(2).c	
+++ b/author-SANCHAY JOSHI(2).c	
@@ -2,8 +2,8 @@
 
 int main()
 {
-	int var = 2147483648;
+	long long var = 2147483648;
 	printf("Sanchay\n\n");
-	printf("Value of var = %d\n",var);
+	printf("Value of var = %lld\n",var);
 	return 0;
 }
diff --git a/author-SANCHAY JOSHI(2).exe b/author-SANCHAY JOSHI(2).exe
new file mode 100644
index 0000000..3b46075
Binary files /dev/null and b/author-SANCHAY JOSHI(2).exe differ
diff --git a/author-SHIVAM MAHAJAN(1).exe b/author-SHIVAM MAHAJAN(1).exe
new file mode 100644
index 0000000..1e88065
Binary files /dev/null and b/author-SHIVAM MAHAJAN(1).exe differ
diff --git a/author-SHIVAM MAHAJAN(2).c b/author-SHIVAM MAHAJAN(2).c
index f39e39a..3a58b9b 100644
--- a/author-SHIVAM MAHAJAN(2).c	
+++ b/author-SHIVAM MAHAJAN(2).c	
@@ -2,6 +2,7 @@
  is equal to that number, the number is called Armstrong number. For example 153.
 Sum of its divisor is 13 + 53;+ 33; = 1+125+27 = 153*/
 #include <stdio.h>
+#include<math.h>
 
 void main(){
     int num,r,sum,temp;
@@ -19,11 +20,11 @@ void main(){
          sum = 0;
 
          while(temp!=0){
-             r=temp / 10;
-             temp%=10;
+             r=temp % 10;
+             temp/=10;
              sum=sum + pow(r,3);
          }
-         if(sum=num)
+         if(sum==num)
              printf("%d ",num);
     }
 printf("\n");
diff --git a/author-SHIVAM MAHAJAN(2).exe b/author-SHIVAM MAHAJAN(2).exe
new file mode 100644
index 0000000..8f3431d
Binary files /dev/null and b/author-SHIVAM MAHAJAN(2).exe differ