indirection requires pointer operand in c

Have a low precedence, and are grouped with their operators from right to left. In this case, the loop condition is always true. However, if the type char is equivalent to unsigned char, then the conversion to int always yields a non-negative value. Then the value of the entire assignment expression c = getchar( ), which is the same char value, is promoted to int for comparison with the constant EOF, which is usually defined as -1 in the header file stdio.h. In the controlling expression of the while statement in this example, getchar( ) returns a value with type int, which is implicitly converted to char for assignment to c. The compiler automatically multiplies the integer by the size of the object referred to by the pointer type, as Example 5-1 illustrates.

Is generally useful only to refer to the elements of an array.Īdding an integer to or subtracting an integer from a pointer yields a pointer value with the same type as the pointer operand. For example, you can modify a pointer to refer to another object a certain number of object sizes away from the object originally referenced. You can use the binary operators + and - to perform arithmetic operations on If a program attempts to divide by zero, its behavior is undefined. For this reason, the expression 8%n in Table 5-6 yields the value 3. However, the result of a modulo operation always has the same sign as the left operand. If both operands in a multiplication or a division have the same sign, the result is positive otherwise, it is negative. The value of n is converted to the type double, because 8.0 has the type double.Įrror: the modulo operation ( %) requires integer operands. Integer promotion: the value of n is promoted to long, because the constant -2L has the type long. Implicit type conversions in arithmetic expressions Implicit type conversion takes place in the evaluation of the following expressions, as shown in Table 5-6 (assume n is declared by short n = -5 ). The result of division with two integer operands is also an integer! To obtain the remainder of an integer division, use the modulo operation (the % operator).

The operands are subject to the usual arithmetic conversions (see ' Conversion of Arithmetic Types' in Chapter 4). In a s ubtraction, either both operands can be pointers to objects of the same type (without regard to type qualifiers), or the minuend (the left operand) can be an object pointer, while the subtrahend (the right operand) has an integer type. In an a ddition, one addend can be an object pointer while the other has an integer type. The operands of all other operators may have any arithmetic type.įurthermore, addition and subtraction operations may also be performed on pointers in the following cases: Only the % operator requires integer operands. The operands of the arithmetic operators are subject to the following rules:

The descriptions are arranged according to the customary usage of the operators, beginning with the usual arithmetic and assignment operators. This section describes in detail the individual operators, and indicates what kinds of operands are permissible.

Indirection requires pointer operand in c