View Compilation Error

0_0_20077841_15471.c: In function 'main':
0_0_20077841_15471.c:10:13: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
             for(int i=0;i<b-1;i++)
             ^
0_0_20077841_15471.c:10:13: note: use option -std=c99, -std=gnu99, -std=c11 or -std=gnu11 to compile your code
0_0_20077841_15471.c:13:13: error: 'cout' undeclared (first use in this function)
             cout<<res<<endl;
             ^
0_0_20077841_15471.c:13:13: note: each undeclared identifier is reported only once for each function it appears in
0_0_20077841_15471.c:13:24: error: 'endl' undeclared (first use in this function)
             cout<<res<<endl;
                        ^
0_0_20077841_15471.c:16:13: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
             for(int i=0;i<b-1;i++)
             ^