Statements are fragments of the C program that are executed in sequence. The body of any function is a compound statement, which, in turn is a sequence of statements and declarations:

int main(void){// start of a compound statementint n=1;// declaration (not a statement)    n= n+1;// expression statementprintf("n = %d\n", n);// expression statementreturn0;// return statement}// end of compound statement, end of function body

There are five types of statements:

[edit]Labels

Any statement can belabeled, by providing a name followed by a colon before the statement itself.

Any statement (but not a declaration) may be preceded by any number oflabels, each of which declaresidentifier to be a label name, which must be unique within the enclosing function (in other words, label names havefunction scope).

Label declaration has no effect on its own, does not alter the flow of control, or modify the behavior of the statement that follows in any way.

[edit]Compound statements

A compound statement, orblock, is a brace-enclosed sequence of statements and declarations.

The compound statement allows a set of declarations and statements to be grouped into one unit that can be used anywhere a single statement is expected (for example, in anif statement or an iteration statement):

if(expr)// start of if-statement{// start of blockint n=1;// declarationprintf("%d\n", n);// expression statement}// end of block, end of if-statement

Each compound statement introduces its ownblock scope.

The initializers of the variables with automaticstorage duration declared inside a block and the VLA declarators are executed when flow of control passes over these declarations in order, as if they were statements:

int main(void){// start of block{// start of blockputs("hello");// expression statementint n=printf("abc\n");// declaration, prints "abc", stores 4 in nint a[n*printf("1\n")];// declaration, prints "1", allocates 8*sizeof(int)printf("%zu\n",sizeof(a));// expression statement}// end of block, scope of n and a endsint n=7;// n can be reused}

[edit]Expression statements

An expression followed by a semicolon is a statement.

Most statements in a typical C program are expression statements, such as assignments or function calls.

An expression statement without an expression is called anull statement. It is often used to provide an empty body to afor orwhile loop. It can also be used to carry a label in the end of a compound statement or before a declaration:

puts("hello");// expression statementchar*s;while(*s++!='\0');// null statement

[edit]Selection statements

The selection statements choose between one of several statements depending on the value of an expression.

[edit]Iteration statements

The iteration statements repeatedly execute a statement.

[edit]Jump statements

The jump statements unconditionally transfer flow control.

[edit]References

[edit]See also

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