View Compilation Error

0_0_19893143_21703.c: In function 'main':
0_0_19893143_21703.c:44:9: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
         for (int i = 1; i <= n; i++)
         ^
0_0_19893143_21703.c:44:9: note: use option -std=c99, -std=gnu99, -std=c11 or -std=gnu11 to compile your code
0_0_19893143_21703.c:46:18: error: redefinition of 'i'
         for (int i = m; i <= n; i++) {
                  ^
0_0_19893143_21703.c:44:18: note: previous definition of 'i' was here
         for (int i = 1; i <= n; i++)
                  ^
0_0_19893143_21703.c:46:9: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
         for (int i = m; i <= n; i++) {
         ^