foo.c:2:1: warning: missing braces around initializer [-Wmissing-braces]
 int g[201][201]={0};
 ^
foo.c:2:1: warning: (near initialization for 'g[0]') [-Wmissing-braces]
foo.c: In function 'main':
foo.c:8:5: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
     for(int i=1;i<=n;i++){
     ^
foo.c:8:5: note: use option -std=c99, -std=gnu99, -std=c11 or -std=gnu11 to compile your code
foo.c:17:14: error: redefinition of 'i'
      for(int i=1;i<=n;i++){
              ^
foo.c:8:13: note: previous definition of 'i' was here
     for(int i=1;i<=n;i++){
             ^
foo.c:17:6: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
      for(int i=1;i<=n;i++){
      ^
foo.c:19:9: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
         for(int j=1;j<=n;j++)
         ^
foo.c:25:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^